Scanning and enlarging question.

<p>I am going to be flatbed scanning a print that is 8x10 (no negative available) and making a print from that scan 32x40. Image quality is critical and 8x10 print is all I have to work with.<br>

I would like to know what settings I should be scanning at to get optimal quality at the larger size? Or any info you can provide that will be useful in the process.<br>

I am fairly new to scanning so any advice would be greatly appreciated.</p>

<p>Scan at 600dpi. Try to adjust color, contrast to make it looks like the print as much as possible. I doubt that you can get very high quality with what you have.</p>

<p>Thanks, I will do that. I understand the quality will be limited, however I want to get the best quality out of what I have.</p>

<p>Save your initial scan to a non-compressed image file format. Tif is good. Jpg is not.</p>

<p>http://www.scantips.com/</p>

<p>If you want to make the print 32x40 it would be better to scan it at 1200 ppi. That way it will enlarge to 32x40 at 300 dpi. If you scan it at 600 ppi, you will have to either print it at 150 dpi or uprez the scan. Neither are ideal.</p>

<p>Peter</p>

 

<p>I think with an 8x10 print scanning at 300 dpi will be sufficient. When scanning prints the only time I resort to 600 dpi is with contact prints from medium format negatives, where there's a lot of detail to be mined. 8x10 scanned at 600 dpi (or 1200!) is going to make for a pretty big file...<br>

I think you'll find a more conclusive answer by simply <em>trying</em> different dpi's and seeing how it goes.</p>

<p>How far away from the viewer will the 32x40" print be?<br /> It will likely not look too great with the nose touching the print, but will be OK from some distance, <em>x</em>, away....<br /> The greater the viewing distance, the lower pixel size you can get away with.<br /> Of course, even with post-processing you won't really be able to get more than you start with, although with some luck you can make it <em>seem</em> better.</p>

<p>The print you're scanning is probably printed from a file at 300 or 360ppi. Thats all there is, and you'll capture all the detail there is by scanning at that setting. Its not like scanning film where there might be 4000ppi worth of detail in there.</p>

<p>Even with interpolation you're looking for a big enlargement , so I hope the original print is immaculate. Brace yourself for the possibility that what you want may not be available to you at a quality level you're happy with. I'd make a 20" x 16" test print from one quarter of the file you make, and look at that from the same distance as you'd want to view the final print, before risking a 40" x 32" print. </p>

<p> </p>

<p>Rather than figuring out the "correct" dpi to scan at, save yourself some effort. Check the manual or spec sheet to find out the optical resolution of the scanner. That's the highest resolution that the lens itself can resolve; anything past that is effectively going to be interpolated. Then scan everything you want to enlarge at that resolution, whatever it is.</p>

<p>If your computer can handle the 1GB file that you're probably going to end up with, then scan at optical resolution. If it can't, then scan at half of optical resolution.</p>

<p>If the print was made with a digital printer then it is true. If it was made optically the resolution can be higher although if it was made from a 35mm negative then there isn't much details beyond the 300dpi.</p>

<p>Ditto the advice to scan at the maximum *optical* resolution of the scanner, without interpolation. And, as suggested, if the file size is unrealistic try half the maximum optical rez. I did that for years a decade ago with a high end flatbed to scan my 8x10 b&w prints and the results were excellent - looked exactly like the original prints.</p>

<p>You might also consider using a high resolution digital camera to copy the 8x10 print. Sometimes flatbed scans can exaggerate texture in prints. Not a problem with glossy or matte paper, but can be aggravating with pearl or other textured surfaces. Unlike flatbeds, copy lights can be adjusted to minimize textures caused by the minute bright spots and shadows.</p>

<p>And ditto, David's suggestion to print a quarter or other fraction of the photo to estimate how it would look at 32x40. I've done something similar in the wet darkroom when wall projecting large prints - I'd first print sections on 8x10 to check the results before committing to larger, more expensive paper.</p>

<p>There is unlikely to be much more than 300dpi of information in the original, and as such your 40x32 inch print can't contain more than about 70 dpi. This might be fine if you're viewing the print from a distance, as you might expect to in a print of that size, but you can't expect it to be be critically sharp or detailed looked at up close, because the fine detail, at that size, just will not be present. You'd need about 1200dpi in the 10x8 original for a top quality print at 40x32, and whilst this could be easily extracted from a 10x8 neg or transparency, the 10x8 print just hasn't got that much data.</p>

<p>Doesn't mean the print wont look good though at a distance - the suggestion to try a section first isn't a bad idea.</p>

<p>Although maybe theoretically an optically-enlarged print (a contact print is different) might possibly contain more than 300 ppi worth of real image detail, so many stars have to align to make it happen (enlarger alignment, enlarging lens performance, film flatness, etc.) that you can pretty much forget about it. <em>However</em>, you cannot assume that you'll capture 300 ppi worth of detail with a 300 ppi scan; if the detail boundaries and the scanning pixels don't align perfectly, you can get some smearing. So I can imagine that in some cases you'll get somewhat better results with, say, a 600 ppi scan, if the scanner has that much true optical resolution. But at some point more scan resolution is meaningless bloat, devoid of substantial additional real image detail. I suspect that a 1200 ppi scan of any enlargement (optical or digital) is probably beyond overkill, and just produces a bigger file for you and the lab to deal with. Yeah, the printer might print at 200, 250, 300, or 400 ppi (or I suspect more likely, 8, 10, 12, or 16 ppmm, which actually works out to 203, 254, 305, or 406 ppi). But the results will probably be as good or better if you let the lab's RIP do upscaling, instead of trying to pull non-existent detail from your scanner with a 1200 ppi scan. But try some small samples (major crops) and see for yourself.</p>